1. Field of the Invention
The invention relates to a device for the treatment of webs or the like, particularly for screen printing, comprising at least one magnetizable working element, particularly a wiper roller or squeegee urged by a magnetic beam towards the web and guided thereover, the web being stationary during the treatment process, the web being interposed between the wiper roller and the beam, the latter being movable on rollers.
2. Description of the Prior Art
Apparatus of this type is particularly used for flat screen printing and therein a magnetic beam is associated with each printing station and is movable along the web. A wiper roller of magnetizable material is displaced in a flat-type screen by displacement of the magnetic beam so that colorant is imprinted on the web. Subsequently, the magnets on the beam are switched off, the flat screen together with the wiper rollers disposed therein are lifted up, and the web, which is attached to a belt or printer's blanket is moved along. In printing machines employing a longitudinal table, the forward movement of the belt does not take place, and a single flat or curved screen is moved either stepwise, or continuously, above a single magnetic beam. According to an upublished proposal, the magnetic beam can also extend in the longitudinal direction of the web and be movable transversely to the latter.
The movement of the magnetic beam has hitherto always been accomplished from the narrow side of the device, whereby a rigid coupling has been provided between the individual beams by means of longitudinally disposed tubes or the like. A rigid coupling of the magnetic beams of this type is always disadvantageous, if a change in the length of the screen is to be made. If only a single magnetic beam is to be employed, it is uneconomical to provide drive means, for example a chain drive, extending over the whole length of the device, since the length of such a device can easily reach 30 meters and more.